Developer Guide

FPGA Optimization Guide for Intel® oneAPI Toolkits

ID 767853
Date 7/13/2023
Public

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Disable Hardware Kernel Invocation Queue (-Xsno-hardware-kernel-invocation-queue)

To direct the Intel® oneAPI DPC++/C++ Compiler to reduce kernel area use by removing kernel invocation queue in SYCL* kernel, include the -Xsno-hardware-kernel-invocation-queue option in your icpx command.

Example

icpx -fsycl -fintelfpga -Xshardware -Xsno-hardware-kernel-invocation-queue <source_file>.cpp
CAUTION:

Using this option may result in longer kernel execution time as the kernel invocation queue allows SYCL runtime environment to queue kernel launches in accelerator so that the accelerator can start execution on the next invocation as soon as previous invocation of the same kernel is complete.

NOTE:

Use the -Xsno-hardware-kernel-invocation-queue option only when your kernel execution time is much greater than the system and SYCL runtime environment overhead hidden by the kernel invocation queue (20-100us), or if the Intel® oneAPI DPC++/C++ Compiler has difficulty fitting your kernel.

Refer to Utilizing Hardware Kernel Invocation Queue for more information about how to utilize the kernel invocation queue.